Cell Specialization

Cell Specialization: Nerve Cell

           The nerve cells, also known as neurons, appear as a normal cell, except there are small "tree-like" structures coming out known as dendrites. These dendrites serve as the main way a nerve cell receives signals from its surroundings or other nerve cells, it functions as a "antennae" for the nerve cell. Within the cell, it is similar to a eukaryotic cell in that it has: a nucleus, nucleolus, ribosomes, mitochondria, lysosomes, endosomes, endoplasmic reticulum, and a Golgi apparatus. Axons extend from the cell itself, and send signals to other nuerons. Each axon is wrapped in a connective tissue sheath called endoneurium, or myelin sheath, which protects the cell and helps it increase the speed of the communication within the body.
           
             The nerve cell has many different functions within the body as it sends messages to the brain, allows us to react to stimulus, carries messages from other neurons to the main cell body, control of both muscles and glands, and mental activity. This "stimulus" that the nerve cells react to can be both chemical and mechanical including: light, touch, and temperature. This stimulus causes an electrochemical change to occur in the dendrites.  The nerve cells are classified as nervous tissue, more specifically the tissue that surrounds each nerve cell is known as endonuerium, which protects the cell; perinuerum, which protects and provides support to the nerve fibers; and epinuerium, which is a dense layer of connective tissue which encloses the nerve.

 Sources:
Waymire, Jack C. "Organization of Cell Types (Section 1, Chapter 8) Neuroscience Online: An Electronic Textbook for the Neurosciences | Department of Neurobiology and Anatomy - The University of Texas Medical School at Houston." Organization of Cell Types (Section 1, Chapter 8) Neuroscience Online: An Electronic Textbook for the Neurosciences | Department of Neurobiology and Anatomy - The University of Texas Medical School at Houston. N.p., n.d. Web. 31 Aug. 2015.
Charand, Ka Xiong. "Nerve Cell." Nerve Cell. N.p., n.d. Web. 30 Aug. 2015. <http://hyperphysics.phy-astr.gsu.edu/hbase/biology/nervecell.html>.

Cardoso, Silvia Helena. "Parts of the Nerve Cell and Their Function." Parts of the Nerve Cell and Their Function. N.p., n.d. Web. 30 Aug. 2015. <http://www.cerebromente.org.br/n07/fundamentos/neuron/parts_i.htm>.

Taylor, Tim. "Nervous System." InnerBody. N.p., n.d. Web. 30 Aug. 2015. <http://www.innerbody.com/image/nervov.html>

Sweetness Lab Response

Cayla Zelanis
Mr. Orre
Anatomy and Physiology period 2
August 24, 2015

Sweetness Lab Response

            In this lab, we tasted different types of carbohydrates and ordered them by the amount of sweetness we tasted. Our goal was to find if the structure of the various carbohydrates changed their level of sweetness. In the end of the lab, we found that the monosaccharides and disaccharides were much sweeter than the polysaccharides that we tasted. We concluded that the reasoning behind the difference of sweetness was the length of the monomers. As the length of the monomers grew, the less sweet the carbohydrate became.
           
             Many of the sugars that were tasted we can relate to food that we eat on a regular basis. Many of the carbohydrates like lactose, which is found in milk; fructose, found in berries, honey, and high fructose corn syrup; and starches,like potatoes, rice, or bread. The carbohydrates that we found to be more "sweet" were the sucrose, glucose, and the fructose. But what made these sugars taste sweet? The sense of "taste" firsts begins when the food reaches with the small pores on our taste buds, known as taste pores, and parts of the food dissolve in the saliva and come into contact with taste receptors. The taste receptors then send a signal found by the taste pores to the gustatory cortex of the brain, which perceives the tastes of different foods detected by the taste pores. Sugar is not the only thing that can be perceived as "sweet", other substances can activate these "sensory cells" or tastes pores that contain nerves. People react differently to different foods based on the sensitivity of their sensory cells. The "basic tastes" that people have are: sweet, sour, bitter, salty and savory, but many people may react differently to the same foods based on the sensitivity. Every cell has a different spectrum to the sensitivity, meaning that one cell may be more sensitive to one "basic taste" over another and a different cell would have a different order of "basic tastes". The level of sweetness is determined by the nerve fibers and to send the information to the gustatory cortex.

                Taking into consideration that each individual cell has a different perception to a certain taste, every individual could rank the sweetness of the tested samples differently. Some individuals taste receptors may be more sensitive to sweet substances over sour substances or vice versa; no two individuals could have the identical perception of the same substances.

Source cited:
How Does Our Sense of Taste Work? U.S. National Library of Medicine, 6 Jan. 2012. Web. 26 Aug. 2015. <http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072592/#i2261.sweetsoursaltybitter>.
Jennifer Poo (picture)